Added a new SDA plotting function.

[DongchenZ]

Description

The new function surpassed the previous version in the following ways:

1. It creates figures based on the alphabetic order of forecast, analysis, and observations.
2. It provides user-defined plotting order by each site, each state variable, or each PFT if the pft.csv path is provided.
3. It provides a user-defined plotting style (so far only colors) for creating figures.
4. The function also creates a database of forecasts, analyses, and observations in a more scalable and generalizable way for future ggplot purposes.
5. For the site option, each page of the PDF file will contain all state variables for each site.

   Motivation and Context

Review Time Estimate

• [ ] Immediately
• [ ] Within one week
• [x] When possible

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] My change requires a change to the documentation.
• [ ] My name is in the list of CITATION.cff
• [ ] I have updated the CHANGELOG.md.
• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.